Problem: Which of these numbers is composite? ${37,\ 43,\ 79,\ 93,\ 97}$
Answer: A composite number is a number that has more than two factors (including 1 and itself). 37, 43, 79, and 97 each have only two factors. The factors of 93 are 1, 3, 31, and 93. Thus, 93 is the composite number.